Shia LaBeouf has been drawing in the crowds as he became part of a bizarre art installation in Los Angeles.

A line of more than 200 curious individuals seeking a few minutes with the 27-year-old actor - wearing a paper bag on his head - snaked along the sidewalk of a busy street, around the block and down an alleyway.

A silent LaBeouf is brazenly on display this week for a performance-art piece titled #IAMSORRY.

"I read he's only doing it a few days, and I just wanted to be part of it," said Amanda Sutton, a 25-year-old graphic designer, as she waited outside the Cohen Gallery on trendy Beverly Boulevard for her staring contest with LaBeouf. "I don't know what's going to happen, other than what I read on Twitter. I keep thinking of what I'll say or do, but I just want it to be spontaneous."

Seated at a small table, wearing a dishevelled tuxedo and the rumpled paper bag with eye holes cut out and the words "I AM NOT FAMOUS ANYMORE" scrawled in black ink across it, LaBeouf began his planned seven-day stint inside the small gallery on February 11. "Shia LaBeouf is sorry," read a press release circulated about the event. "Sincerely sorry."

So why exactly is LaBeouf apologetic? It's never explained, and LaBeouf isn't talking.

The performance-art oddity comes days after LaBeouf posed on the red carpet at the Berlin Film Festival in the same get-up and walked out of a press conference to promote filmmaker Lars von Trier's Nymphomaniac Volume I, the first instalment of a sexually charged two-part drama, after reciting a line once delivered by footballer Eric Cantona.

The Transformers and Disturbia star came under fire last year for borrowing the storyline and dialogue for his short film Howard Cantour.com, which closely resembled the 2007 graphic novel The Death-Ray by Daniel Clowes. LaBeouf has since apologised on Twitter in a series of posts that appear to be directly lifted from other famous mea culpas.

After waiting in line for several hours, attendees were frisked by a security guard in a black suit and ushered inside the gallery. They were asked to choose implements to bring into the space with LaBeouf. The items include a Transformers toy, a bowl of printed tweets, a bottle of cologne, a ukulele and a copy of Clowes' book. No photography was permitted.

One visitor described how the bag-clad LaBeouf stared forward with his tattooed hands on the table and remained silent when asked questions, his once twinkly green eyes devoid of emotion. The only interaction from LaBeouf occurred during a pair of handshakes exchanged at the start and end of the encounter.

The stunt reached a new level of ridiculousness when Stand By Me actor Jerry O'Connell, in collaboration with the comedy site FunnyOrDie.com, began parodying LaBeouf at a gallery next door with #IAMSORRYTOO similarly plastered on the window. Inside, O'Connell donned a paper bag with the words "SUPER FAMOUS" on it.

The line to meet O'Connell was considerably shorter than LaBeouf's queue. O'Connell's one-day lampoon was particularly meta because many folks have drawn parallels between LaBeouf's #IAMSORRY display and artist Marina Abramovic's performance-art piece The Artist Is Present, which featured Abramovic sitting across from visitors at New York's Museum of Modern Art in 2010.

Ultimately, several #IAMSORRY attendees said they were left scratching their heads, unsure if the grocery bag confessional they participated in was part of another meltdown from a former child star, a Joaquin Phoenix-like publicity stunt, an intellectual commentary on copycat culture or something in-between. However, no one queried said they regretted waiting in line.

"I grew up watching him on Evens Stevens, so I never thought I'd be sitting across from him as an adult with a paper bag on his head," said James Gianti, a 21-year-old student who waited in line two hours. "I didn't really know what to expect. It was way more depressing than I thought it would be. He's just sitting there. The whole thing was just really, really depressing."